Inlet design for a pump assembly

ABSTRACT

One embodiment includes a housing ( 14 ) and an impeller ( 34 ). The housing ( 14 ) comprises an inlet portion ( 24 ) which in turn defines an inlet passage ( 28 ). The inlet passage ( 28 ) leads to the impeller ( 34 ) and directs fluid flow substantially perpendicular with respect to an axis of rotation ( 38 ) of the impeller ( 34 ).

This application claims the benefit of U.S. Provisional Application Ser.No. 60/947,521 filed Jul. 2, 2007.

TECHNICAL FIELD

The field to which the disclosure generally relates includes productsincluding an inlet design for a pump assembly and the pump assemblyitself.

BACKGROUND

Fluid pumps having impellers are commonly designed with a fluid inletpassage that directs fluid axially in relation to the impeller at acenter of the impeller or at its blades. One example of such a fluidpump is a secondary air pump assembly that supplies secondary air to anautomotive exhaust system to reduce pollutants in the exhaust gases.

SUMMARY OF EXEMPLARY EMBODIMENTS OF THE INVENTION

One embodiment of the invention includes a product comprising at least ahousing and impeller. The housing comprises an inlet portion which inturn defines an inlet passage. The inlet passage leads to the impellerand directs fluid flow substantially perpendicular with respect to anaxis of rotation of the impeller.

Another embodiment of the invention includes a product comprising a pumpassembly which itself comprises a housing, an electric motor, and animpeller. The housing forms an inlet portion which defines an inletpassage. The electric motor is at least partially carried by thehousing. The impeller is located in the housing and is driven by theelectric motor. The impeller has a plurality of blades. A center of flowof a fluid coming out of the inlet passage is directed generallyparallel to a radially oriented plane defined by the impeller.

Another embodiment of the invention includes a product comprising asecondary air pump assembly which itself comprises a housing, anelectric motor, and an impeller. The housing comprises an inlet portiondefining an inlet passage, and an outlet portion. The electric motor isat least partially carried by the housing. The impeller is located inthe housing and is driven by the electric motor. The impeller defines anaxis of rotation, a circumference, and a radially oriented plane. Acenter of flow of air coming out of the inlet passage lies perpendicularto the axis of rotation and parallel to the radially oriented plane.

Other exemplary embodiments of the present invention will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whiledisclosing exemplary embodiments of the invention, are intended forpurposes of illustration only and are not intended to limit the scope ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the present invention will become more fullyunderstood from the detailed description and the accompanying drawings,wherein:

FIG. 1 illustrates a schematic of one embodiment of a secondary airsystem that includes a pump assembly.

FIG. 2 illustrates a partial sectional view of one embodiment of theinvention including a product including a pump assembly.

FIG. 3 illustrates a top view of one embodiment of the inventionincluding a product including a pump assembly.

FIG. 4 illustrates a perspective view of one embodiment of an impellershowing several relationships of a center of fluid flow with respect tothe impeller.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The following description of the embodiment(s) is merely exemplary innature and is in no way intended to limit the invention, itsapplication, or uses.

Referring now to FIGS. 1-3, one embodiment of the invention includes aproduct that may be an inlet 10 for a fluid pump designed to increaseoverall efficiency in some embodiments of the fluid pump by, among otherthings, reducing turbulence to thus reduce load and hence current draw.In at least one embodiment, the fluid flow of the fluid pump isincreased by about 1 SCFM, and the current draw is reduced by about2.5-3.0 Amperes. The inlet 10 may be incorporated in a pump assembly 12which in this example is a secondary air pump assembly as used in asecondary air system 13 (FIG. 1) of an automotive exhaust system toreduce pollutants in the exhaust gases. The secondary air system 13 mayalso include an air filter 15 that filters air before it is received inthe pump assembly 12, a secondary air valve 17, and a catalyticconverter 19 which could also be a diesel particulate filter in otherembodiments. In this system, the pump assembly 12 discharges air to thecatalytic converter 19 to mix with exhaust gases coming from an engine21. Skilled artisans will know the general construction, arrangement,and operation of these types of secondary air systems such that a morecomplete description will not be given here.

The inlet's 10 design may be incorporated in other pump assemblieshaving impellers such as those that pump air or liquid, and those withimpellers of the semi-open type, enclosed type, two-stage compressiontype, and the like. The pump assembly 12 may be of the regenerative pumptype. Referring to FIGS. 2 and 3, the pump assembly 12 shown may includea housing 14 to accommodate an electric motor 16 that drives an impeller34 for energizing air. The housing 14 may at least partially carry theelectric motor 16 and may shelter and support the impeller 34, and mayalso provide acoustic insulation for one or both of them. The housing 14may be made in one-piece, or made up of several pieces subsequently puttogether. It may be constructed of a metal such as aluminum or steel, ora plastic such as a polymeric or composite material, or the like. Still,in some embodiments, some parts may be composed of one material whileother parts may be composed of another material. As shown, the housing14 may include a first cover 20 adjacent the impeller 34 and a secondcover 22 adjacent the electric motor 16. The first cover 20 may form aninlet portion 24 and an outlet portion 26 which respectively define aninlet passage 28 and an outlet passage (not shown). In otherembodiments, the inlet portion 24 may be formed partially by the firstcover 20 and partially by another portion of the housing 14, or may beformed entirely by another portion of the housing 14 and not at all bythe cover 20. The inlet passage 28 may have a circular cross-sectionwith a diameter of 22.4 mm, or it may have other size diameters and mayhave various irregularly shaped cross-sections like a polygon. The exactsize and shape may be partly dependent on desired fluid flowcharacteristics. The outlet passage may also have a circularcross-section or other cross-sections.

The electric motor 16 may provide mechanical energy to drive the pumpassembly 12. The electric motor may be a d.c. motor or other type. Insome embodiments, the electric motor 16 may be enclosed by the secondcover 22 as shown, and in other embodiments, the electric motor 16 maybe attached to and supported by the housing 14 without the cover 22. Theelectric motor 16 may drive the impeller 34 through a shaft 32. Andalthough not specifically shown, the electric motor 16 may furtherinclude a stator surrounding at least one rotor. Skilled artisans willknow the general construction, arrangement, and operation of these typesof motors such that a more complete description will not be given here.

The impeller 34 energizes incoming air from the inlet portion 24 andthen discharges the air out the outlet portion 26. The impeller 34 isrotated about the shaft 32 to direct air outwardly to an annular channel36 and away from the center of rotation. The impeller 34 may come inmany designs including the one shown in FIG. 4. In general, the impeller34 may have a circular or cylindrical shape which defines an axis ofrotation 38, a circumference 40, and a radially oriented plane 42. Theaxis of rotation 38 shown may be an imaginary line that projects throughthe center of rotation and along an axis of the cylindrical shape of theimpeller 34. The circumference 40 shown may be an imaginary circleoutside of the axis of rotation 38 and generally around a circumferenceof the cylindrical shape of the impeller 34. And the radially orientedplane 42 shown may be an imaginary plane that is perpendicular to theaxis of rotation 38 and that may intersect the circumference 40, beparallel to the circumference 40, or both. In this regard, the term“axially” may describe a direction that is along an axis of thecylindrical shape of the impeller 34, including along the axis ofrotation 38; the term “circumferentially” may describe a direction thatfollows a circumference of the cylindrical shape of the impeller 34,including the circumference 40; and the term “radially” may describe adirection that follows a radius of the cylindrical shape of the impeller34, and that may be perpendicular to the axis of rotation 38, in theradially oriented plane 42, or both.

Still referring to FIG. 4, the impeller 34 may be made in one-piece, ormade up of several pieces subsequently put together. It may beconstructed of a metal such as aluminum or steel, or a plastic such as apolymeric or composite material, or the like. Still, in someembodiments, some parts may be composed of one material while otherparts may be composed of another material. The impeller 34 may have agauge or axial thickness of 12 mm, or it may have other size gaugesdepending partly upon the desired fluid flow. As shown, the impeller 34may include a plurality of axially and radially extending vanes orblades 44 disposed circumferentially about a body 46. The blades 44 maybe designed and oriented in a number of ways, including that shown asbeing axially oriented with respect to the impeller 34. For example, theblades 44 may be slightly bent as shown, concave or convex, flat, or thelike. Each of the plurality of blades 44 may have a face 48 looking in adirection of rotation A of the impeller 34. Each face 48 has a geometriccenter which lies at about the middle of the face. The body 46 may havea center of rotation about the axis of rotation 38, and may define asurface 50 which may be parallel with or may lie within the radiallyoriented plane 42.

When in use, the pump assembly 12 generally energizes fluid, such asair, coming from the inlet passage 28 and discharges the air out theoutlet passage. The inlet portion 24 may be designed to direct airtoward the impeller 34 such that the air flows substantiallyperpendicular with respect to the axis of rotation 38 and generallyparallel to the radially oriented plane 42. For the sake of description,the flow of air may be represented by a center of flow line B in FIG. 4.In one embodiment, a center of flow line B′ may be directedsubstantially tangentially with respect to the circumference 40. Inother words, at least some of the flow of air may contact thecircumference 40 at a single point. Of course, not all of the flow ofair in this embodiment is tangential in this sense. In anotherembodiment, a center of flow line B″ is directed generally at the middleof the faces 48 that are adjacent the inlet portion 24 or exposed to theflow of fluid. In another embodiment, a center of flow line B′″ isdirected at and perpendicularly intersects the axis of rotation. In allembodiments, the center of flow B may reduce turbulence by virtue of itsdirection.

The above description of embodiments of the invention is merelyexemplary in nature and, thus, variations thereof are not to be regardedas a departure from the spirit and scope of the invention.

1. A product comprising: a housing (14) of a pump assembly (12), thehousing (14) comprising an inlet portion (24) which defines an inletpassage (28); an impeller (34) located in the housing (14); and whereinthe inlet passage (28) leads to the impeller (34) and directs fluid flowsubstantially perpendicular with respect to an axis of rotation (38) ofthe impeller (34).
 2. A product as set forth in claim 1 wherein theinlet portion (24) has a circular cross-section which defines the inletpassage (28).
 3. A product as set forth in claim 1 wherein the impeller(34) comprises a plurality of blades (44) disposed about thecircumference of the impeller (34), the blades (44) each comprising aface (48) that is oriented axially with respect to the impeller (34). 4.A product as set forth in claim 3 wherein the inlet passage (28) directsthe fluid flow generally at the faces (48) of the blades (44) adjacentthe inlet passage (28).
 5. A product as set forth in claim 3 wherein acenter of flow (B) of the fluid coming out of the inlet passage (28) isdirected generally at a middle of the faces (48) of the blades (44)adjacent the inlet passage (28).
 6. A product as set forth in claim 1wherein a center of flow (B) of the fluid coming out of the inletpassage (28) is directed substantially tangentially with respect to acircumference (40) defined by the impeller (34).
 7. A product as setforth in claim 6 wherein the center of flow (B) of the fluid liesparallel with a radially oriented plane (42) defined by the impeller(34).
 8. A product as set forth in claim 1 wherein a center of flow (B)of the fluid coming out of the inlet passage (28) is directedsubstantially perpendicular with respect to the axis of rotation (38)and intersects the axis of rotation (38).
 9. A product as set forth inclaim 1 wherein a center of flow (B) of the fluid coming out of theinlet passage (28) lies parallel with a radially oriented plane (42)defined by the impeller (34).
 10. A product comprising: a pump assembly(12) comprising: a housing (14) forming an inlet portion (24) whichdefines an inlet passage (28); an electric motor (16) carried at leastpartially by the housing (14); an impeller (34) located in the housing(14) and being driven by the electric motor (16), the impeller (34)comprising a plurality of blades (44); and wherein a center of flow (B)of a fluid coming out of the inlet passage (28) is directed generallyparallel to a radially oriented plane (42) defined by the impeller (34).11. A product as set forth in claim 10 wherein the center of flow (B) ofthe fluid is directed substantially tangentially with respect to acircumference (40) defined by the impeller (34).
 12. A product as setforth in claim 10 wherein the plurality of blades (44) each have a face(48) oriented axially with respect to the impeller (34), and wherein thecenter of flow (B) of the fluid is directed generally at a middle of thefaces (48) adjacent the inlet passage (28).
 13. A product as set forthin claim 10 wherein the center of flow (B) of the fluid liesperpendicular to an axis of rotation (38) of the impeller (34).
 14. Aproduct as set forth in claim 13 wherein the center of flow (B) of thefluid intersects the axis of rotation (38).
 15. A product as set forthin claim 13 wherein the housing (14) further comprises an outlet portion(26) that lies perpendicular to the axis of rotation (38) of theimpeller (34).
 16. A product comprising: a secondary air pump assembly(12) comprising: a housing (14) comprising an inlet portion (24) whichdefines an inlet passage (28), and an outlet portion (26); an electricmotor (16) carried at least partially by the housing (14); an impeller(34) located in the housing (14) and being driven by the electric motor(16), the impeller (34) defining an axis of rotation (38), acircumference (40) outside of the axis of rotation (38), and a radiallyoriented plane (42) lying perpendicular to the axis of rotation (38) andintersecting the circumference (40); and wherein a center of flow (B) ofair coming out of the inlet passage (28) lies perpendicular to the axisof rotation (38) and lies parallel to the radially oriented plane (42).17. A product as set forth in claim 16 wherein the center of flow (B) issubstantially tangential to the circumference (40).
 18. A product as setforth in claim 16 wherein the impeller (34) comprises a plurality ofblades (44) that each has a face (48) oriented axially with respect tothe impeller (34), and wherein the center of flow (B) is directedgenerally at a middle of the faces (48) adjacent the inlet passage (28).19. A product as set forth in claim 16 wherein the center of flow (B)intersects the axis of rotation (38).